Genomic landscapes of breast cancer in African populations: a systematic review.

Abstract

Breast cancer in African women carries high mortality, yet genomic data from continental African cohorts are limited. We conducted a systematic review of next-generation sequencing based observational cohort studies of somatic breast cancer genomes in women of African ancestry, from January 2004 to September 2024. Extracted genomic features-driver mutations, copy-number alterations, structural-variants, tumour mutational burden and mutational signatures-were contrasted against TCGA's Black/African American and White reference cohorts. Ten studies from seven countries met inclusion criteria. Main findings were higher rate of triple-negative breast cancer, higher rate of TP53 and lower rate of PIK3CA mutations compared with TCGA White. African tumours also exhibited elevated TMB, CNA and SV burden. Mutational signatures revealed enriched homologous recombination deficiency and APOBEC activity. Despite small, heterogeneous cohorts and regional gaps, these distinct somatic landscapes suggest PARP, PI3K and immunotherapy targets. Coordinated sequencing efforts are urgently needed to drive precision oncology in Africa.